Classic anime and you ppl don't mention Starblazers(yamato), fail! before u watch the crap of the more current gundam shows, watch the original series, even the ovas up to and including Char's counterattack, then watch the non UC crap.

as to robotech, watch the unbutchered versions of Macross, Southern Cross and Mospeada, much better stories.

[ Some notes about Ghost in the Shell ]
The original started with the movie Ghost in the Shell. Following the movie comes Ghost in the Shell 2: Innocence, and that's it. No more. Ghost in the Shell: Stand Alone Complex is an anime series based in the same universe as the original movie, but beyond this it has absolutely no direct connection (one is not a continuation of the other). Stand Alone Complex 2nd GIG is essentially just the 2nd season to Stand Alone Complex. The Laughing Man and Individual Eleven "movies" are just chopped up compilation "movies" of the first and second seasons of Stand Alone Complex, respectively. Solid State Society is a movie that takes place after the events of 2nd GIG, a direct continuation of the Stand Alone Complex series continuity.

For continuity reference:

Original movie continuity:
- Ghost in the Shell
- Ghost in the Shell 2: Innocence

[ Some notes on Neon Genesis Evangelion ]
It's a 26 episode series, that's it. However, it is followed by Death & Rebirth which replaces episode 26 and adds a new ending. Following that, there's the End of Evangelion movie which nullifies both the series ending (ep. 26) and Death & Rebirth, and provides a whole new ending (again), which is supposed to be the "true" ending of the Evangelion series. At least, until...

The REBUILD of Evangelion nullifies everything (the entire original series and it's movies) and completely remakes the entire story in a new way, intended to be the "definitive" version of Evangelion by series creator Hideaki Anno. This comes from Anno's desire to finally recreate Eva "as he wanted it to be" in the beginning, now that he is no longer constrained by technological and budget limitations. The Rebuild movies loosely adapt episodes from the series into the new format, and at points completely change the story entirely. The first movie retells roughly the first 6 episodes of the series in a manner that's relatively true to the original series. The second movie takes it from ep. 7 to ep. 19 of the original series, but the changes to the story make it an entirely new story that deviates greatly from the original series. Because of the changes in the second movie, the third movie ends up being a completely new story unrelated to the original series, ep.20 and beyond of the original series is essentially dead and gone. And the final film, 4.0, has not been released yet (even in Japan), so I can't say much here.

The REBUILD of Evangelion:
- Evangelion 1.0: You Are (Not) Alone
- Evangelion 2.0: You Can (Not) Advance
- Evangelion 3.0: You Can (Not) Redo
- Evangelion: Final

[ Some notes about the Gundam Metaseries ]
Now, Gundam is a bit tricky to start out with. Once you're hooked, I'd say watch them all for many various reasons, but to start out, that's the hard part.

Die-hard Gundam fans are almost always die-hard "Universal Century" (or "UC" for short) fans, which is to say that they're fans of the Gundam series, movies, etc - that are all a part of the original Gundam's timeline canon (the "Universal Century" if you will). Later, popular Gundam series like Gundam Wing, Gundam SEED, and Gundam 00 do not take place in the UC at all, and are in separate timelines. Gundam Wing is part of the "After Colony" timeline, Gundam SEED is in the "Cosmic Era" timeline, and "Gundam 00" is in the "Anno Domini" timeline. A series/movie/etc in one timeline, does not intersect or have any relation to a series/movie/etc in another timeline; it has to be in the same timeline to be directly related beyond being a "Gundam" series.

If you don't care where you start, and wouldn't mind watching the original Mobile Suit Gundam (1979), I'd say start there. It's quite a good series if you don't mind the highly dated animation quality and dialogue. Otherwise, start on something a bit more modern and up to date like Gundam SEED, which is said by many (while not true) to be a remake of the classic Mobile Suit Gundam; or Gundam 00 which is said by some (while also not true) to be a remake of Gundam Wing.

Personally, I didn't quite care for Mobile Suit Gundam, but fell in love with practically all other Gundam series (including others in the Universal Century), and still consider SEED to be one of my favorites (which die-hard fans will claim as one of the worse in Gundam history).

It's all about personal preference really, but if you want an easy way in, go with SEED or 00.

Ok I got a list of anime's you could watch you will like, but I will warn you that some might be a little hard to follow for some people, I added some little notes and bolded the ones a highly recommend to anyone:

Yu Yu Hakusho (oldy but goody)
Mushishi (not necessarily gritty but it is interesting)Code Geass (excellent anime, mech)
Death Note (great anime)Clannad/After Story (will admit to liking this anime, not gritty at all since it is a "slice of life" anime but I feel I need to always recommend it)
Monster (very dark anime, excellent, kinda long but so worth it)
Birdy the Mighty DecodeRurouni Kenshin (classic, excellent anime)
School Rumble (all humor, not gritty, one of my favorites, can make anyone laugh)
Full Metal Panic/Fumoffu (all humor, not gritty, one of my favorites, can make anyone laugh)Black Lagoon (excellent anime, overlooked by many)
Darker Than Black (good anime, dark, but only watch first season since second is garbage imo)
Basilisk (good anime)Elfen Lied (excellent anime, dark, has a lot of nudity that seems excessive but you get used to it fyi)
Deadman Wonderland (good anime)Hellsing (great anime, oldy but goody)
Gunslinger Girl (good anime, weird at times)Neon Genesis Evangelion (classic must watch)
Blood+ (okay anime)Afro Samurai (excellent anime)